An incident analog signal, for example comprising information situated within a desired frequency range (desired channel, for example), and frequency components situated outside of the desired frequency range (channels adjacent to the desired channel), generally undergoes, after amplification in an amplifier stage, for example a low-noise amplifier stage, one or more frequency transpositions in order to convert it into baseband. The incident signal down-converted into baseband is then intended, after filtering, to be converted into digital form in order to subsequently undergo specific processing operations, such as, for example, channel decoding processing notably comprising a demodulation and source decoding processing.
When the frequency transposition is carried out by successively inverting the sign of the incident analog signal at the rhythm of a periodic signal (transposition signal) to control a set of switches, and when the transposed signal is delivered to an output capacitor, belonging to or forming, for example, a filter, this can lead, in particular, to a degradation of the gain of the chain owing to stray capacitances of the amplifier stage causing, at certain moments, a partial discharge of the output capacitor.